The present invention relates to load bearing surfaces, and more particularly to elastomeric fabric load bearing surfaces, such as the seat or back of a chair or bench, or the support surface of a bed, cot or other similar body-supporting product.
There is a continuing effort to develop new and improved load bearing surfaces for use in body-supporting applications, such as the support surfaces in seating, cots and beds. It is desirable for load bearing surfaces to be, among other things, comfortable, durable and relatively inexpensive to manufacture and assemble.
There is an increasing use of elastomeric load bearing fabrics in the seating industry. For example, there are a variety of office chairs available from well-known suppliers that include seat and back portions manufactured from elastomeric fabric. In a conventional application of this type, a layer of elastomeric fabric is stretched across a frame over an opening. In use, the elastomeric fabric elastically deflects to provide a resilient, somewhat cushion-like response to a load. Elastomeric load bearing fabrics are typically manufactured from a weave of elastomeric monofilaments and multifilament yarns, but may include other woven and non-woven constructions. For example, some elastomeric fabrics are woven entirely from elastomeric monofilaments (i.e. the fill yarns are replaced by elastomeric filaments). Elastomeric load bearing fabrics provide a comfortable, elastic, ventilated surface. Although elastomeric fabric surfaces can be quite comfortable in many applications, they are not ideal in all body-support applications. Conventional elastomeric fabric surfaces typically deflect like a sling when a load is applied. Some ergonomists refer to this type of deflection as “hammocking” and consider it undesirable because it can cause the hips to rotate upward. This rotation of the hips can cause discomfort, particularly over extended periods. To minimize the degree of hammocking, many elastomeric fabric surfaces are stretched even more tightly than might otherwise be desired. Although this can reduce the amount of deflection that occurs under load (and therefore reduce the degree of hammocking), it can have an unintended negative impact on comfort. More specifically, stretching the fabric tighter will reduce the cushion-like feel of the surface making it feel more like a tightly stretched drum.
Accordingly, there remains a need for an elastomeric fabric load bearing surface that overcomes the limitation of existing constructions.